阅读说明：本技术 一种硅基异质结电池的退火设备及退火方法 (Annealing equipment and annealing method of silicon-based heterojunction battery ) 是由 不公告发明人 于 2021-01-30 设计创作，主要内容包括：本发明公开了一种硅基异质结电池的退火设备及退火方法,所述硅基异质结电池包括非晶硅层、透明导电膜层和电极栅线,所述退火设备包括加热腔室；加热光源,在所述加热腔室外的一相对侧设置有若干个；其中,所述加热光源包括长波激光源和短波激光源,所述长波激光源发射第一激光,所述第一激光的频率低于所述透明导电膜层的禁带宽度且高于所述非晶硅层的禁带宽度,所述短波激光源发射第二激光,所述第二激光的频率高于所述透明导电膜层的禁带宽度。本发明采用不同波段的激光对电池的非晶硅层和透明导电膜层进行分段加热和分段退火,避免透明导电膜层受到影响而降低其材料的光电性能,使电极栅线也可以有多种选择,有利于提高异质结电池的效率。(The invention discloses annealing equipment and an annealing method of a silicon-based heterojunction battery, wherein the silicon-based heterojunction battery comprises an amorphous silicon layer, a transparent conductive film layer and an electrode grid line, and the annealing equipment comprises a heating chamber; the heating light sources are arranged on the opposite sides outside the heating cavity; the heating light source comprises a long-wave laser source and a short-wave laser source, the long-wave laser source emits first laser, the frequency of the first laser is lower than the forbidden band width of the transparent conductive film layer and higher than the forbidden band width of the amorphous silicon layer, the short-wave laser source emits second laser, and the frequency of the second laser is higher than the forbidden band width of the transparent conductive film layer. The invention adopts the lasers with different wave bands to carry out sectional heating and sectional annealing on the amorphous silicon layer and the transparent conductive film layer of the cell, thereby avoiding the influence on the transparent conductive film layer to reduce the photoelectric property of the material, enabling the electrode grid line to have various choices and being beneficial to improving the efficiency of the heterojunction cell.)

1. The utility model provides an annealing equipment of silicon-based heterojunction battery, silicon-based heterojunction battery includes amorphous silicon layer, transparent conductive film layer and electrode grid line, annealing equipment includes heating chamber, its characterized in that, annealing equipment still includes:

a plurality of heating light sources are arranged on one opposite side outside the heating cavity and used for radiating the silicon-based heterojunction cells;

the heating light source comprises a long-wave laser source and a short-wave laser source, the long-wave laser source emits first laser, the frequency of the first laser is lower than the forbidden band width of the transparent conductive film layer and higher than the forbidden band width of the amorphous silicon layer, the short-wave laser source emits second laser, and the frequency of the second laser is higher than the forbidden band width of the transparent conductive film layer.

2. The annealing apparatus of claim 1, wherein the first laser wavelength emitted by the long wave laser source is in the range of 650nm to 900 nm.

3. The annealing apparatus according to claim 1, wherein the second laser wavelength emitted by the short-wave laser source is in the range of 300nm-330 nm.

4. The annealing apparatus according to claim 1, wherein a position detecting device is further disposed on the heating light source, and the position detecting device is located between the long-wave laser source and the short-wave laser source, and is used for detecting the position information of the silicon-based heterojunction cell in the heating chamber.

5. The annealing apparatus according to any one of claims 1 to 4, wherein the silicon-based heterojunction cells are carried on a carrier plate, the bottom of which is provided with a conveyor for transporting the carrier plate between the inside and the outside of the heating chamber.

6. The annealing apparatus according to claim 5, wherein the carrier is a glass carrier or a metal carrier.

7. The annealing apparatus according to any one of claims 1 to 4, wherein N heating light sources are provided on an opposite side of the heating chamber, and N heating light sources are uniformly arranged on each side, where N is equal to or greater than 3.

8. An annealing method for a silicon-based heterojunction cell, the annealing method comprising:

heating the amorphous silicon layer of the silicon-based heterojunction cell by adopting a long-wave laser source, and carrying out primary annealing on the silicon-based heterojunction cell;

heating the transparent conductive film layer and the electrode grid line of the silicon-based heterojunction battery by adopting a short-wave laser source to perform secondary annealing of the silicon-based heterojunction battery,

the long-wave laser source emits first laser, the frequency of the first laser is lower than the forbidden band width of the transparent conductive film layer and higher than the forbidden band width of the amorphous silicon layer, the short-wave laser source emits second laser, and the frequency of the second laser is higher than the forbidden band width of the transparent conductive film layer.

9. The annealing method according to claim 8, wherein the primary annealing is performed at 50-200mJ/cm by a first laser emitted from the long-wavelength laser source³The energy of the silicon-based heterojunction cell radiates the outer surface of the silicon-based heterojunction cell, the single radiation time is 50-100ns, the radiation frequency is 1-20Hz, and the radiation times are 10-50;

the secondary annealing is that the second laser emitted by the short-wave laser source is used for emitting laser light with the wavelength of 100-175mJ/cm³The energy of the silicon-based heterojunction battery is radiated on the outer surface of the silicon-based heterojunction battery, the single radiation time is 20-50ns, the radiation frequency is 5-20Hz, and the radiation times are 5-30.

10. The annealing method according to claim 8 or 9, wherein the primary annealing is temperature-controlled annealing, and the temperature control range is 100-400 ℃; the secondary annealing is temperature-controlled annealing, and the temperature control range is 100-500 ℃.

Technical Field

The invention belongs to the technical field of silicon-based heterojunction battery production, and particularly relates to annealing equipment and an annealing method for a silicon-based heterojunction battery.

Background

After silicon wafer texturing, an amorphous silicon film layer, a transparent conductive film layer (TCO) and screen printing of grid lines are completed, silver paste solidification is carried out for 5min, and different film layers of the silicon-based heterojunction cell (HJT) need to be baked at the same temperature and in the same atmosphere to complete oven annealing. The silicon heterojunction silicon-based heterojunction battery can obviously improve the open voltage of the battery due to the excellent passivation effect of the amorphous silicon layer; but also because of the existence of the amorphous silicon layer, after the screen printing process of the grid line is finished, only low-temperature baking annealing can be carried out. The low-temperature annealing process not only limits the photoelectric performance of the TCO material, but also limits the selection of the grid line silver paste.

Disclosure of Invention

In view of the above, the invention provides annealing equipment and an annealing method for a silicon-based heterojunction battery, which adopt lasers with different wave bands to perform segmented heating and segmented annealing on an amorphous silicon layer and a transparent conductive film layer of the battery, and abandon the phenomenon that the transparent conductive film layer is affected due to integral heating and annealing so as to reduce the photoelectric property of the material, so that grid lines serving as electrodes can be selected in various ways, and the efficiency of the heterojunction battery is improved.

In order to achieve the technical purpose, the invention adopts the following specific technical scheme:

in a first aspect, an annealing apparatus for a silicon-based heterojunction battery is provided, where the silicon-based heterojunction battery includes an amorphous silicon layer, a transparent conductive film layer, and an electrode grid line, the annealing apparatus includes a heating chamber, and the annealing apparatus further includes:

a plurality of heating light sources are arranged on one opposite side outside the heating cavity and used for radiating the silicon-based heterojunction cells;

the heating light source comprises a long-wave laser source and a short-wave laser source, the long-wave laser source emits first laser, the frequency of the first laser is lower than the forbidden band width of the transparent conductive film layer and higher than the forbidden band width of the amorphous silicon layer, the short-wave laser source emits second laser, and the frequency of the second laser is higher than the forbidden band width of the transparent conductive film layer.

According to a specific implementation manner of the embodiment of the invention, the first laser wavelength range emitted by the long-wave laser source is 650nm-900 nm.

According to a specific implementation manner of the embodiment of the invention, the second laser wavelength range emitted by the short-wave laser source is 300nm-330 nm.

According to a specific implementation manner of the embodiment of the present invention, a position detection device is further disposed on the heating light source, and the position detection device is located between the long-wave laser source and the short-wave laser source and is configured to detect position information of the silicon-based heterojunction battery in the heating chamber.

According to a specific implementation manner of the embodiment of the present invention, the silicon-based heterojunction battery is carried on a carrier plate, and a conveying device is disposed at the bottom of the carrier plate, and is configured to transport the carrier plate between the inside and the outside of the heating chamber.

According to a specific implementation manner of the embodiment of the invention, the carrier plate is a glass carrier plate or a metal carrier plate.

According to a specific implementation manner of the embodiment of the present invention, N heating light sources are disposed on an opposite side of the heating chamber, and the N heating light sources on each side are uniformly arranged, where N is greater than or equal to 3.

In a second aspect, there is provided an annealing method for a silicon-based heterojunction cell, the annealing method comprising:

heating the amorphous silicon layer of the silicon-based heterojunction cell by adopting a long-wave laser source, and carrying out primary annealing on the silicon-based heterojunction cell;

heating the transparent conductive film layer and the electrode grid line of the silicon-based heterojunction battery by adopting a short-wave laser source to perform secondary annealing of the silicon-based heterojunction battery,

the long-wave laser source emits first laser, the frequency of the first laser is lower than the forbidden band width of the transparent conductive film layer and higher than the forbidden band width of the amorphous silicon layer, the short-wave laser source emits second laser, and the frequency of the second laser is higher than the forbidden band width of the transparent conductive film layer.

According to a specific implementation manner of the embodiment of the invention, the primary annealing is that the first laser emitted by the long-wave laser source is used for emitting 50-200mJ/cm³The energy of the silicon-based heterojunction cell radiates the outer surface of the silicon-based heterojunction cell, the single radiation time is 50-100ns, the radiation frequency is 1-20Hz, and the radiation times are 10-50;

the secondary annealing is that the second laser emitted by the short-wave laser source is used for emitting laser light with the wavelength of 100-175mJ/cm³The energy of the silicon-based heterojunction battery is radiated on the outer surface of the silicon-based heterojunction battery, the single radiation time is 20-50ns, the radiation frequency is 5-20Hz, and the radiation times are 5-30.

According to a specific implementation manner of the embodiment of the invention, the primary annealing is temperature-controlled annealing, and the temperature control range is 100-400 ℃; the secondary annealing is temperature-controlled annealing, and the temperature control range is 100-500 ℃.

By adopting the technical scheme, the invention can bring the following beneficial effects:

the invention utilizes the penetrability of long-wave band laser, adopts the long-wave band laser to directly irradiate and heat the amorphous silicon layer below the transparent conductive film layer, and completes the annealing of the amorphous silicon layer by utilizing the annealing process meeting the requirement of the amorphous silicon layer; then heating the transparent conductive film layer and the electrode grid line by using short-wave-band laser, and completing the annealing process of the transparent conductive film layer and the electrode grid line by using the annealing process which meets the requirements of the transparent conductive film layer and the electrode grid line; the two annealing processes cannot influence each other, so that the photoelectric property of the TCO material cannot be influenced, the TCO material and the electrode grid line material have more selectivity, and the efficiency of the heterojunction cell is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural view of an annealing apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic view of a heating light source according to an embodiment of the present invention;

FIG. 3 is a flow chart of an annealing process in accordance with an embodiment of the present invention;

wherein: 1. a heating chamber; 2. a silicon-based heterojunction cell; 3. a carrier plate; 4. a heating light source; 41. a long-wave laser source; 42. a short-wave laser source; 43. a position detecting device.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that various aspects of the embodiments are described below within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the disclosure, one skilled in the art should appreciate that one aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number of the aspects set forth herein. Additionally, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than the number, shape and size of the components in practical implementation, and the type, quantity and proportion of the components in practical implementation can be changed freely, and the layout of the components can be more complicated.

In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that aspects may be practiced without these specific details.

Annealing equipment

First, an annealing apparatus of an embodiment of the present invention, which may be used for annealing of solar cells such as silicon-based heterojunction cells, is described with reference to fig. 1, but it should be understood that the annealing apparatus can also be used for annealing of other types of solar cells. As shown in fig. 1, the annealing apparatus includes a heating chamber 1, a carrier plate 3, and a heating light source 4.

The heating chamber 1 may be, for example, a vacuum heating chamber, may be made of a high temperature resistant material such as ceramic, and may be formed in a cylindrical, cubic, or the like shape.

The carrier plate 3 is disposed in the heating chamber 1 and used for carrying the silicon-based heterojunction battery 2, and the material of the carrier plate 3 is a heat-resistant material that does not react with the silicon-based heterojunction battery 2, such as glass or metal.

The heating light source 4 may be plural and disposed at the opposite side outside the heating chamber 1 for irradiating the silicon-based heterojunction cell 2 carried on the carrier plate 3 for heat treatment such as annealing. In the embodiment of the present invention, the heating light sources 4 may be uniformly arranged, alternatively, the heating light sources 4 may be arranged in a non-uniform manner, that is, the distance between two adjacent heating light sources 4 may be different.

In the embodiment of the present invention, the heating light source 4 includes different types of laser light sources, specifically, the heating light source 4 includes a long-wave laser light source 41 and a short-wave laser light source 42, the long-wave laser light source 41 emits first laser light, and the frequency of the laser light emitted by the long-wave laser light source is lower than the forbidden bandwidth of the transparent conductive film layer of the silicon-based heterojunction cell 2 and higher than the forbidden bandwidth of the amorphous silicon layer of the silicon-based heterojunction cell 2, and is used for annealing the amorphous silicon layer of the silicon-based heterojunction cell 2. That is, the long-wavelength laser source 41 is required to emit laser light having a frequency lower than the forbidden band width of the transparent conductive film layer and higher than the forbidden band width of the amorphous silicon layer, and a light source capable of emitting laser light having a frequency within this range is referred to as the long-wavelength laser source 41.

The short-wave laser source 42 emits second laser, the frequency of the emitted laser is higher than the forbidden bandwidth of the transparent conductive film layer of the silicon-based heterojunction battery 2, and the short-wave laser source is used for annealing the transparent conductive film layer and the electrode grid line of the silicon-based heterojunction battery 2. That is, the long-wavelength laser source 42 is required to emit laser light having a frequency higher than the forbidden band width of the transparent conductive film layer and higher than the forbidden band width of the amorphous silicon layer, and a light source capable of emitting laser light having a frequency within this range is referred to as a short-wavelength laser source 42.

The term "forbidden bandwidth" refers to the energy between the highest energy level of the conduction band and the lowest energy level of the valence band, for example: the forbidden band width of germanium is about 0.66eV at room temperature (300K); the forbidden band width of silicon is about 1.12 eV; the forbidden band width of gallium arsenide is about 1.424 eV; the forbidden band width of cuprous oxide is about 2.2 eV.

In the embodiment of the present invention, the fact that the frequency of the laser is higher or lower than the forbidden band width means that the laser bandgap value at the frequency is higher or lower than the forbidden band width. For the calculation of the band gap value, the band gap value can be calculated according to the formula (ahv) ^2 ═ a (hv-eg), where a is the absorption coefficient, hv is the photon energy corresponding to the wavelength laser, h is the planck constant, v is the photon frequency, and eg obtained by calculation is the band gap value.

The long-wavelength laser source 41 and the short-wavelength laser source 42 may employ, for example, a split gas laser, a solid-state laser, a semiconductor laser, a fiber laser, and a dye laser.

In the embodiment of the present invention, the emission laser wavelength range of the long-wave laser source 41 is 650-900 nm. The transparent conductive film layer can be made of metal oxide such as indium tin oxide and the like, the forbidden bandwidth is 3-7eV, the forbidden bandwidth of the amorphous silicon layer is 1-2eV, and as the wavelength of laser emitted by the long-wave laser source 41 needs to be capable of penetrating through the transparent conductive film layer and reaching the amorphous silicon layer, and the radiation energy of the laser needs to be absorbed by the amorphous silicon layer, the laser with the wavelength of 650nm-900nm is adopted, so that the annealing temperature of 100 plus 400 ℃ is reached, and the temperatures of the transparent conductive film layer and the electrode grid line are not too high.

The emission laser wavelength of the short-wave laser source 42 is 300nm to 330 nm. The radiation to the transparent conductive film layer needs to ensure that the radiation energy of the short-wave laser source 42 is absorbed by the transparent conductive film layer and the silver electrode grid line, and the radiation energy and the silver electrode grid line reach the annealing temperature of 100-500 ℃, so in the embodiment of the invention, laser with the wavelength of 300-330 nm is adopted.

In the embodiment of the present invention, the long-wave laser source 41 and the short-wave laser source 42 are integrated together, and as shown in fig. 2, the heating light source 4 may further be provided with a position detecting device 43 for detecting the position information of the silicon-based heterojunction cell 2 in the heating chamber 1.

The position detection device 43, which may be, for example, a schottky barrier diode, is fixed between the long-wave laser source 41 and the short-wave laser source 42. The irradiation directions of the long-wave laser source 41, the position detection device 43 and the short-wave laser source 42 are kept consistent and perpendicular to the carrier plate 3. Schottky barrier diodes are used to determine whether the silicon-based heterojunction cell 2 is in the irradiatable range of the long-wave laser light source 41 and the short-wave laser light source 42.

It should be understood that the position detecting device 43 is not limited to being a schottky barrier diode, but may be other sensors as long as it can detect the position information of the silicon-based heterojunction cell 2 in the heating chamber 1.

Furthermore, in an embodiment of the invention, the bottom of the carrier plate 3 is provided with a not shown transfer device for transferring the carrier plate 3 between the interior and the exterior of the chamber.

According to one embodiment, the transfer device includes a motor, a transfer rack, and a slide bar. The slide bar is fixed at the bottom of the heating chamber 1, the bottom of the support plate 3 is provided with a sliding groove, the side part is fixed with a sliding rack, and the support plate 3 is arranged on the slide bar through the sliding groove. The motor is fixed inside the heating chamber 1, and a power gear is arranged on the rotating shaft and meshed with the sliding rack.

According to another embodiment, the conveying means may also take the form of a conveyor belt.

And after finishing silicon wafer texturing, amorphous silicon film layer, transparent conductive film layer and screen printing grid line and 5min silver paste solidification, annealing the silicon-based heterojunction battery 2.

The motor is controlled to convey the carrier plate 3 to the outside of the heating chamber 1, the silicon-based heterojunction cell 2 is placed on the carrier plate 3 in parallel, and then the motor is controlled to convey the carrier plate 3 into the heating chamber 1 until the position detection device 43 detects that the silicon-based heterojunction cell 2 is in the irradiation range of the long-wave laser source 41 and the short-wave laser source 42.

When the heat treatment is carried out, firstly, the long-wave laser source 41 is utilized to irradiate the amorphous silicon layer in the silicon-based heterojunction battery 2, and the annealing of the amorphous silicon layer is completed; irradiating the transparent conductive film layer and the electrode grid lines of the silicon-based heterojunction battery 2 by using a short-wave laser source 42 to finish annealing the transparent conductive film layer and the electrode grid lines; after the two times of annealing are finished, the motor is controlled to convey the carrier plate 3 out of the heating chamber 1.

In the embodiment of the present invention, three silicon-based heterojunction cells 2 can be uniformly placed on the carrier plate 3, and the combination of the long-wave laser source 41, the position detection device 3 and the short-wave laser source 42 is six groups, that is, six heating light sources 4 are provided, as shown in fig. 1, three groups are fixed on the top of the heating chamber 1 and used for radiating the upper surfaces of the silicon-based heterojunction cells 2; three sets are fixed on the bottom of the heating chamber 1 and used for radiating the lower surface of the silicon-based heterojunction cell 2.

That is, the annealing apparatus for a silicon-based heterojunction cell in the embodiment of the present invention includes a heating chamber 1, and the annealing apparatus further includes:

a plurality of heating light sources 4 arranged on an opposite side of the heating chamber and used for radiating the silicon-based heterojunction cells 2 loaded on the carrier plate 3;

the heating light source 4 includes a long-wave laser source 41 and a short-wave laser source 42, the long-wave laser source 41 emits first laser, the frequency of the first laser is lower than the forbidden band width of the transparent conductive film layer and higher than the forbidden band width of the amorphous silicon layer, the short-wave laser source 42 emits second laser, and the frequency of the second laser is higher than the forbidden band width of the transparent conductive film layer.

According to one embodiment of the invention, the first laser wavelength emitted by the long-wave laser source 41 is in the range 650nm to 900nm, preferably 775 nm.

According to a particular embodiment of the invention, the second laser wavelength emitted by the short-wave laser source ranges from 300nm to 330nm, preferably 315 nm.

According to an embodiment of the present invention, a position detecting device 43 is further disposed on the heating light source 4, and the position detecting device 43 is located between the long-wave laser source 41 and the short-wave laser source 42 for detecting the position information of the silicon-based heterojunction cell in the heating chamber 1.

According to one embodiment of the present invention, the bottom of the carrier plate 3 is provided with a conveyor for transporting the carrier plate 3 between the inside and the outside of the heating chamber.

According to an embodiment of the present invention, the carrier 3 is a glass carrier or a metal carrier.

According to an embodiment of the present invention, N heating light sources 4 are disposed on an opposite side of the heating chamber, and the N heating light sources on each side are uniformly arranged, where N is greater than or equal to 3 and is an integer.

Annealing method

Next, an annealing method of a silicon-based heterojunction cell of an embodiment of the present invention is described with reference to fig. 3, the method including the steps of:

passing a long-wave laser source 41 at 50-200mJ/cm in the heating chamber 1³The energy of (2) is irradiated to the outer surface of the silicon-based heterojunction cell, and the single irradiation time is 50-100ns, the radiation frequency is 1-20Hz, and the radiation frequency is 10-50 times, so as to complete the one-time annealing treatment of the silicon-based heterojunction cell 2.

In the heating chamber 1, at 100-175mJ/cm by short wave laser source 42³The energy of the energy is radiated on the outer surface of the silicon-based heterojunction battery 2, the single radiation time is 20-50ns, the radiation frequency is 5-20Hz, and the radiation times are 5-30 times, so that the secondary annealing treatment of the silicon-based heterojunction battery 2 is completed.

In the embodiment of the invention, the primary annealing adopts temperature-controlled annealing, and the temperature is controlled at 100-400 ℃.

In the embodiment of the invention, the secondary annealing adopts temperature-controlled annealing, and the temperature is controlled at 100-500 ℃.

That is, in the embodiment of the present invention, the annealing apparatus is used to anneal the silicon-based heterojunction cell, and the method includes:

in the heating chamber 1, the long-wave laser source 41 is adopted to heat the amorphous silicon layer of the silicon-based heterojunction cell 2, and primary annealing of the silicon-based heterojunction cell 2 is carried out;

in the heating chamber 1, the short-wave laser source 42 is adopted to heat the transparent conductive film layer and the electrode grid line of the silicon-based heterojunction battery 2, so as to perform secondary annealing of the silicon-based heterojunction battery 2,

the long-wave laser source 41 emits first laser, the frequency of the first laser is lower than the forbidden bandwidth of the transparent conductive film layer and higher than the forbidden bandwidth of the amorphous silicon layer, the short-wave laser source 42 emits second laser, and the frequency of the second laser is higher than the forbidden bandwidth of the transparent conductive film layer.

According to an embodiment of the invention, the primary annealing is performed by emitting a first laser beam at 125mJ/cm by the long-wave laser source³The energy of the silicon-based heterojunction cell radiates the outer surface of the silicon-based heterojunction cell, the single radiation time is 75ns, the radiation frequency is 10Hz, and the radiation frequency is 30 times;

the secondary annealing is carried out at 135mJ/cm by second laser emitted by the short-wave laser source³Energy of (2) irradiating the exterior of the silicon-based heterojunction cellAnd the single radiation time is 35ns, the radiation frequency is 12Hz, and the radiation times are 17 times.

According to a specific embodiment of the present invention, the primary annealing is a temperature controlled annealing at a temperature of about 250 ℃; the secondary annealing is temperature-controlled annealing, and the temperature is about 300 ℃.

According to the embodiment of the invention, different laser sources are adopted to anneal the amorphous silicon layer, the transparent conductive film layer and the grid line of the silicon-based heterojunction battery at different temperatures, so that the annealing time is shortened; meanwhile, the photoelectric property of the TCO is improved by annealing at a higher temperature; and finally, the annealing process of the grid line is also ensured.

Next, effects by the present invention scheme are described. The electrical properties of the transparent conductive film layer are detected, the transparent conductive film layer prepared by the process of the embodiment of the invention and the transparent conductive film layer prepared by the conventional process are used for testing the carrier concentration, the carrier mobility and the sheet resistance, the test results are normalized and shown in the following table 1, and the results show that compared with the conventional process, the carrier concentration of the transparent conductive film layer prepared by the process of the embodiment of the invention is improved by about 5%, and the carrier mobility is also improved by 20%.

TABLE 1 transparent conductive film layer electric property test table

TCO process	Concentration of carriers	Carrier mobility	Square resistor
				This example Process	1.05	1.2	0.90
Conventional process	1.00	1.00	1.00

In another embodiment, the HJT battery prepared by the process of the embodiment of the present invention and the HJT battery prepared by the conventional process are tested, and the test results are shown in table 2, where the conversion efficiency Eff of the HJT battery prepared by the process of the embodiment of the present invention is improved by about 3%, the short-circuit current Isc is improved by 1.5%, and the fill factor FF is improved by 1.3%.

Table 2 electrical property test meter for heterojunction battery

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.